The CYP-derived eicosanoids including EETs and 20-HETE are at the center of the proposed research in each project of this Program Project. Accordingly, a centralized core facility to measure their levels in tissues and biological fluids is critical for the execution and successful completion of the proposed studies. Mass spectrometry remains the state-of-the art methodology for quantitative analysis of eicosanoids and their derivatives as well as for structural identification of new lipid molecules. The centralized Mass Spectroscopy Core will continue to provide investigators in this program with a consolidated, highly specialized, well equipped and professionally staffed unit capable of performing a variety of mass spectroscopy-based analyses of various eicosanoids, including advanced liquid chromatography-tandem mass spectrometry (LC/MS/MS) and gas chromatography-mass spectrometry (GC/MS). This centralized core facility ensures uniformity of assay results between the different projects while maintaining the highest quality of analytical precision and accuracy achievable; it will keep complete, computerized and centralized records as well as well-defined quality control guidelines for each method. Consequently, the specific objectives of the Core are: 1) To establish and ensure uniform standardized methods for preparing samples for analyses including sample collection, extraction and storage till analyses; 2) To provide reliable, reproducible and timely mass spectroscopy analyses of CYP-derived eicosanoids in tissues and biological fluids (plasma, urine, etc.); 3) To maintain computerized records of raw data and analyzed results; 4)To assist investigators in developing new methods. Utilization of mass spectrometry at many levels is an important feature ofthis Program Project proposal. This stems from the recognition that mass spectrometric analyses provide adequate sensitivity, specificity, and selectivity required for detection and characterization of subpicomolar quantities of eicosanoids. No other technique of comparable sensitivity is currently available for their characterization and quantification. All Program Project Investigators will utilize the mass spectrometry for one or more aspects of quantitative, structural and chiral analyses.